Heat-resistant broad-bandwidth liquid droplet generators

A liquid droplet generator, comprising:

• a delivery tube having a wall and an exit orifice;
• an electromechanical driver element disposed to transmit pressure pulses to said wall;
• and
• a power supply coupled to said electromechanical driver element;
• wherein said electromechanical driver element comprises:
• current windings circumferentially surrounding said delivery tube and acoustically coupled thereto, said current windings comprising a first current winding adjacent to a second current winding, said current windings also coupled to said power supply;
• electrical insulation disposed between said first and second current windings;
• wherein said first and second current windings are disposed so that a current travelling through said first winding will be of opposite polarity to a current travelling through said second winding;
• and
• a force retaining ring substantially surrounding said current windings.

A liquid droplet generator, comprising:

• a delivery tube having a wall and an exit orifice;
• an electromechanical driver element disposed to transmit pressure pulses to said wall;
• and
• a power supply coupled to said electromechanical driver element;
• wherein said electromechanical driver element comprises:
• an electromagnetic field generator substantially surrounding the circumference of said delivery tube;
• and
• an armature circumferentially coupled to said delivery tube and proximate to said electromagnetic field generator, said armature comprising soft magnetic material.

A liquid droplet generator, comprising:

• a delivery tube having a wall and an exit orifice;
• an electromechanical driver element disposed to transmit pressure pulses to said wall;
• and
• a power supply coupled to said electromechanical driver element;
• wherein said electromechanical driver element comprises:
• an insulator coupled to said delivery tube and circumferentially surrounding said delivery tube over a portion of the length of said delivery tube, said insulator comprising an acoustically conductive, thermally insulating material;
• a first conductor substantially surrounding said insulator and coupled thereto;
• a dimension-changing means coupled to said first conductor;
• a force retaining ring of electrically conductive material substantially surrounding said dimension-changing means and coupled thereto;
• said first conductor and said force retaining ring coupled to said power supply;
• and
• cooling means disposed to draw heat away from said first conductor and said force retaining ring.

A liquid droplet generator, comprising:

• a delivery tube having a wall and an exit orifice, said delivery tube adapted to transmit a liquid jet stream through said exit orifice;
• an electromechanical driver element disposed to receive said liquid jet stream, said driver element comprising:
• a magnetic field yoke having arms corresponding to points of maximum field intensity;
• and
• current windings disposed about a portion of said magnetic field yoke;
• and
• a power supply coupled to said current windings of said electromechanical driver element.

A high-temperature liquid droplet generator, comprising:

• a chamber adapted to receive a high-temperature liquid having a temperature in excess of the Curie temperature of a piezoelectric material, said chamber including a discharge orifice at one end;
• a heater positioned proximate the chamber and operable to maintain the high-temperature liquid inside the chamber at about said high temperature;
• and
• a pulsing energy source coupled to the chamber, said pulsing energy source being operable in a tuned relation with the chamber and the high-temperature liquid therein to generate pressure pulses in the liquid so as to discharge the liquid from the chamber as droplets related in number to the pressure pulses producing the droplets.

A method for generating droplets from a high-temperature liquid, comprising:

• delivering a high-temperature liquid having a temperature in excess of the Curie temperature of a piezoelectric material to a liquid droplet generator in a jet, the liquid droplet generator comprising:
• a delivery tube having a wall and an exit orifice, said delivery tube adapted to receive said liquid jet;
• and
• an electromechanical driver element coupled to said wall;
• electrically exciting said electromechanical driver element to compress said wall;
• and
• expelling at least one liquid droplet from said exit orifice.

A method for generating liquid droplets, comprising:

• delivering liquid to a liquid droplet generator in a jet, the liquid droplet generator comprising:
• a delivery tube having a wall and an exit orifice, said delivery tube adapted to receive said liquid jet;
• and
• an electromechanical driver element coupled to said wall;
• electrically exciting said electromechanical driver element to compress said wall;
• and
• expelling at least one liquid droplet from said exit orifice;
• wherein said electromechanical driver element comprises a piezoelectric crystal acoustically coupled to said wall and thermally insulated from said wall.

A method for generating liquid droplets, comprising:

• delivering liquid to a liquid droplet generator in a jet, the liquid droplet generator comprising:
• a delivery tube having a wall and an exit orifice, said delivery tube adapted to receive said liquid jet;
• and
• an electromechanical driver element coupled to said wall;
• electrically exciting said electromechanical driver element to compress said wall;
• and
• expelling at least one liquid droplet from said exit orifice;
• wherein said exciting and expelling steps comprise:
• supplying pulsed current to said driver;
• generating a pulsed magnetic field substantially and symmetrically surrounding said delivery tube in response to said pulsed current;
• alternately expanding and contracting a portion of said wall of said delivery tube radially in response to said pulsed magnetic field;
• vibrating said liquid jet in said delivery tube in response to said expansion and contraction;
• inducing a waveform on said liquid jet in said delivery tube in response to said vibrations;
• and
• amplifying said waveform to cause said liquid jet to break into droplets after exiting said orifice.

A method for generating liquid droplets, comprising:

• delivering liquid to a liquid droplet generator in a jet, the liquid droplet generator comprising:
• a delivery tube having a wall and an exit orifice, said delivery tube adapted to receive said liquid jet;
• and
• an electromechanical driver element coupled to said wall;
• electrically exciting said electromechanical driver element to compress said wall;
• and
• expelling at least one liquid droplet from said exit orifice;
• wherein said electromechanical driver element comprises a magnetostrictive element acoustically coupled to said wall and thermally insulated from said wall.

A method of generating liquid droplets, comprising:

• delivering liquid to a liquid droplet generator in a jet, the generator comprising:
• a delivery tube having a wall and an exit orifice;
• an electromagnetic driver element disposed to receive said liquid jet stream, said driver element comprising:
• a magnetic field yoke having a plurality of arms at spaced intervals;
• and
• current windings disposed about a portion of said magnetic field yoke;
• heating said delivery tube;
• supplying current to said current windings of said driver element;
• generating a magnetic field from said magnetic field yoke, said magnetic field having maximum points of maximum field intensity corresponding to said arms of said field yoke;
• transmitting a liquid jet stream through said exit orifice and through said magnetic field;
• and
• breaking the liquid jet stream into a series of droplets in response to said magnetic field, said droplets having a spacing corresponding to the spacing of said points of maximum field intensity.